The present invention relates, to a collapsible bulk storage containment system, that has the rigid features of a fiber board box, along with the flexibility, or collapsibility, and liquid integrity, of a bulk bag.
Previously manufactured bulk shipping containers have usually used either a bag approach, or a rigid container approach, both of which have their advantages and their disadvantages. The bag type containers are easily shipped, and stored, in an empty condition, but frequently they generally do not have sufficient rigidity, especially when filled with liquid, or fluent material, to allow stacking of the filled containers.
They also have presented problems in loading, and particularly, in unloading, in that they can easily shift during transport, making it substantially impossible to unload them with mechanical devices, such as fork lifts, without penetrating the bags. The rigid containers clearly have sufficiently rigid structure to allow stacking, when filled, or partially filled, with liquid, or fluent material, but they cannot be collapsed, and thus take up a lot of room for transportation and storage when empty. Many of the known bag and rigid containers do not have any provision for compartmentalization of the storage region, in order to provide for multiple materials to be loaded in the container in a segregated fashion.
One recent attempt to overcome the above-mentioned difficulties is found in U.S. Pat. No. 4,903,859, issued to N. C. Derby et al. This Patent, discloses a bag-like container, which is made from two-layers of flexible material, which form a series of pockets therebetween. At least two rigid members are inserted into these pockets, to form opposing rigid side walls, when the container is assembled. Access spouts are provided for filling, or discharging, liquid contents. The top and bottom of the container are closed by excess material, there being no top and bottom members, or portions, as such. A somewhat similar approach is found in U.S. Pat. No. 3,896,991.
In the bag-like container, depicted in U.S. Pat. No. 4,903,859, the ends of the container are formed by tubular plastic sheet sections, that extend axially beyond the ends of the rigid stiffening members contained within pockets in the container side walls. The tubular plastic sheet sections are collapsed together on the container central axis, after which flexible ties are tightened around the collapsed sheet sections. The process is quite similar to the process used to close the mouth of a conventional trash bag. The patentees, [N.C. Derby et al.], indicate that the collapsed sheet sections at the opposite ends of the container are access spouts, for adding liquid to the container, or withdrawing liquid from the container.
One problem with the bag-like container of U.S. Pat. No. 4,903,859 is that the tied, collapsed plastic end sections, contribute very little transverse rigidity to the container. The container is not very stable when placed upright on a flat surface, since any lateral offsetting of the container center of gravity from the container central axis, can allow the container to tilt, or possibly topple over. Also, when the container is placed on a flat support surface, the lowermost tied collapsed plastic end section in contact with the support surface, will, inevitably, be forced upwardly into the space circumscribed by the rigid container side walls, thereby generating a stress on the flexible tie, that is tightened around the collapsed plastic end section. In this circumstance, there is a potential danger that the flexible tie will break, or become loosened, so as to produce a leaking condition, at the lower end of the bag-like container.